Apparatus for treating toxic gases



gully D. 1.... EASTMAN 2,258,943

APPARATUS FOR TREATING TOXIQGASES Filed April 8, 1939 2 Sheets-Sheet lPatented July 7, 1942- UNITED STATES I PATENT OFFICE APPARATUS FOR-2,288,943 rnaa'rmc 'roxrc cases Don L. Eastman, Water-town, -N. Y.Application April 8,1939, Serial No. 266,827

' 1 Claim. (01. 23-288) This invention relates to an improved method andapparatus for treating toxic gases for the purpose of rendering themnon-toxic. In a particular aspect the invention relates to a-method ofcatalytically converting the carbon monoxide Figure 7 is a detailshowing of the catalytic materia1 employed in Figure 6. 1

As shown in the drawings, inthe preferred method of eflectuating theinvention a catalytic chamber, designated generally by the numeral l, isinterposed in the exhaust pipe 2 of an internal combustion motor such asin an automobile. The chamber I, as shown, may be constructed of a tubeof any suitable metal and associate a catalytic chamber with the exhaustof an internal combustion motor in which the toxic carbon monoxide iscatalytically oxidized to the innocuous carbon dioxide.

Another object of the invention is to embody such catalytic chamber inthe exhaust pipe of an automobile. A

Yet another object of the invention is'to devise a chamber of the typedescribed'which is catalytically eflicient and yet does notsubstantially detract from the efiiciencyvoi the motor itself. 'Afurther object. is to provide as a garage accessory a device which maytemporarily be attached to the exhaust line of a motor and which isoperative to oxidize the carbon monoxide content of the gas flowingtherethrough.

With these and other equally important and related objects in view theinvention comprehends the concept of effectively oxidizing the carbonmonoxide content of exhaust gases by an improved catalytic agency. Y

In order to enable a more ready comprehension of the principles of theinvention there is shown in the accompanying drawings a preferredphysical embodiment in which:

Figure 1 is a longitudinal section of the improved unit.

Figure 2 is an enlarged cross section taken on line 2-2 of Figure 1.

is provided with the end walls 3 and 4. These end walls, as will beappreciated, may be removable. a short pipe or tube section, shown atland 6 respectively, by means 'of which the chamber is coupled in theexhaust line. The chamber may be locked in the exhaust line ,in anysuitable manner, as for example by means of the clamps i and 8 whichlock the tube sections 3 and 4 to the cooperating sections of theexhaust pipe.

The chamber I may be mounted at any suitable place .in the exhaust linebetween the exhaust manifold and the muilier preferably near the motorso that the catalysis is accelerated by utilizing the gases at anoptimum high temperature. If desired the catalytic chamber may beinterposed in the exhaust line after the muffler or may be embodied inthe mufller structure itself.

As will be observed from an inspection of Figure l, the chambercomprisesessentially a spaced series of catalytic sections A and anadjacentand alternate series of expansion sections B.

The sections A contain catalytic material; to

be more particularly described, which is efiec-.

tive to insure the oxidation of the carbon monoxide content of the gasto carbon dioxide. This catalytic materia1 l6 which, as shown is in theform of hard porous granular masses may be retained in position in anydesired manner. One effective and preferred method comprises theutilization of open mesh screen tubes 1 l which,

as shown are provided at each end with the wire mesh-walls l2.

The screen units H preferably are made up of a standardized size so asto facilitate menu-'- iacture, installation and replacement. As shown,

Figure 3 is a modified form of the device adapted particularly forgarage use.

Figure 4 is a view, similar to Figure l, showing a modified form ofcatalytic chamber.

Figure 5 is a cross section takenon line 5-5 of Figure 4. Figure 6 is alongitudinal section of a further modification under the invention.

particularly in Figure 2 these units are of such size that a givennumber (four in the illustrafrom longitudinal movement by suitable meansEach of these walls is provided with tion A.

It will be observed that with this type of structure intimate contact ofthe gases with the catalytic material is insured without, however,imposing undue back pressure on the motor. The exhaust gases (indicatedby the arrows) entering at one end of the unit C pass through theseveral tube units and between open spaces between the respectivelyadjacent tube units and the walls of the chamber. After passagetherethrough the gases enter the expansion chamber .3 where an intimateadmixture is insured of the gas passing through the catalytic masses andthat passing through the open spaces. Thereafter the gases again passthrough a catalytic section in which, it will be observed, catalytictube units are disposed in alignment with the open spaces of the firstcatalytic unit. In this manner a certain degree of free passage spacefor the gas is left in each catalytic section so that undue backpressure on the engine is not built up. However, by utilizingrespectively circumferentially displaced tube units in adjacent sectionsin conjunction with the intermediate expansion and mixing chamberscontact of substantially all of the exhaust gas with the catalyticmasses is insured.

It will be observed also that the spaces between the adjacent tube unitsin each section establish free passages of restricted cross section.Flow of gas through these at relatively high velocity thus establishesan aspirating effect and tends to positively induce gas flow through thecatalytic tube units.

As previously indicated the invention also contemplates the utilizationof a catalytic chamber as a garage accessory. In large garages wheremany motors may be operating at the same time there is a real danger ofa development of a dangerously high concentration of carbon monoxide,especially when the garage is not adequately ventilated. According tothe invention, danger of this type may completely be avoided byproviding a simple unit which may readily be attached temporarily to theexhaust pipe of a car. Such a unit is indicated in Figure 3. Thiscomprises a catalytic chamber 30 of the same type as that disclosed inFigures 1 and 2, that is to say it comprehends a spaced series ofcatalytic sections and an alternate series of expansion chambers orspaces. The chamber is closed at the two ends 3i and 32 and at such endsare provided with the inlet and discharge pipes 33 and 34 respectively.A flexible tubing 35 of any suitable material is adapted to be attachedat one end to the pipe 33 by suitable means such as the clamp 36. Theopposite end of the tube 35 is properly conformed so as to fit over thetail section of the exhaust pipe. Such end may be provided with suitableclamping means (not shown) so that it may be detachably secured to thetail pipe. Similarly a second section of flexible tubing 31 of anydesired length may be attached to discharge pipe 34 by means of a clamp33. I

This unit may quickly be attached to the tail pipe of a car so that themotor may be operated in closed areas without any danger of carbonmonoxide poisoning. Such a unit may similarly be employed in any othercircumstances in which it is desired to, remove carbon monoxide fromdischarge gases.

In effectuating the invention any catalytic material which is effectiveto oxidize carbon monoxide may be utilized. Preferably the catalyticmaterial should be in the form of granular masses, as shown, whichshould be of sumcient strength to withstand the shocks and Jars incidentto car operation without disintegrating and powdering. Such catalyst,may, for example, comprise porous rigid mass of suitable catalyticmaterial such as manganese dioxide, mixtures of manganese dioxide,copper oxide, cobaltic oxide and the like.

Porous, rigid, effective catalysts may be made up by fusing a metaloxide or mixture of metal oxides together with a binder material undertemperature conditions which insure intumescence in the mass and maythen be chilled to establish a porous or vesicular structure providing alarge exposed surface of the catalytic material.

A catalytic material which is particularly effective comprises a rigidmass including cupric oxide, manganese dioxide and cobaltic oxide. Thismay be made up by first homogeneously mixing substantially equal partsof the three components in the dry powdered form. To this dry mixturethere is then added a quantity of sodium silicate in the approximateproportions of three pounds of the oxide mixture to one quart of sodiumsilicate solution (40 B.). The mass is then stirred until it assumes aviscous, rubbery consistency, in which form it may be moulded into anydesired shape such as sticks, granular masses and the like. with thementioned 'proportion of ingredients the mass hardens to a solid uponair drying for a period of about 48 hours. .The air dried product isthen burned or heated to fusion or incipient fusion in a suitablefurnace or in an open flame. By heating the mass to a cherry red,incipient fusion takes place and the mass intumesces or swells up toapproximately twice its original volume. The mass is then quickly cooledto retain this expanded structure and the resulting product ischaracterized by a high degree of porosity and hardness. After suchcooling the material may, if desired be broken up into pieces of thedesired size which are then packed in the open mesh tubes previouslydescribed. This catalytic product apparently comprises a siliciousskeletal porous unit in which the catalytic oxides are homogeneouslydispersed. This high porosity coupled'with the uniform dispersion of theoxides through the mass insures accelerated catalytic action.

The utilization of the described catalytic material, i. e. a catalyticmass which may readily be formed into any desired shape permits theemployment of specifically different types of catalyst chambers. Thus asshown in Figures 4 and 5 a catalyst chamber operating on the sameessential principle of that described may be constructed withoututilizing the open mesh tubular container II. In other words, thecatalytic material may be moulded in the form of, so to speakself-sustaining members. I

As shown in the modification illustrated in Figures 4 and 5, thecatalytic material is moulded in the form of porous rigid tubular units40 of any desired length, internal and external diameter. A group ofsuch tubular units may be mounted in a chamber M such that adjacentunits respectively abut. Each section of such units may be maintained inposition in the container 4! by means of the perforate retainer means 52which preferably comprisesopen mesh wire units or perforated metaldiscs.

In accordance with the major principles of the invention the severalcatalytic sections are spaced apart so as to provide a free gasexpansion space therebetween. Such spacing may be established by meansof the spacer rings 33.

The container or tube M is provided with removable end members 136 (onebeing shown) which are provided with pipe sections 45 adapt ed to beconnected in the exhaust line as. The catalyst chamber may be connectedin the exhaust line in any suitable manner as for example, by utilizingclamping means of the type shown in Figure 1.

As will be appreciated, the utilization of catalytic material of theself-sustaining type is not limited to the particular form of unitsshown in Figures 4 and 5. These may be made up in any desired eiiectiveshape as for example in the form of perforate disc-like members shown inFigures 6 and 7. In this form of the invention the catalytic units M aremoulded or preformed in the general shape of a disc. As shown the discis provided with a large number of perforations 68. The size and numberof such perforations may be controlled so as to insure the desired gasvelocity through the catalytic chamber. Such units are preferably formedwith circumferential serrations or grooves 62 to permit the passage ofgas around the circumferential edge.

and 6 operate in the same efiective manner as that shown in Figure 1.The entering gas passes alternately through the catalytic sections andthe expansion sections in such a manner as to insure optimum contactwtih the catalytic material and consequent effective oxidation of thecarbon monoxide but with the minimum of back sion spaces in which thecatalytic sections are These units may be assembled in a catalystchamber in the manner previously described,

that is to say at spaced distances so as to provide alternate catalyticand free gas expansion areas. As shown the units as are mounted withinthe catalytic chamber $3 such that the free edges abut the internalwalls of the chamber. The units are maintained in the desired spacedrelationship by means of the spacer rings 66. If desired the internalwall of the chamber may be provided with projecting lugs or one or morelongitudinal ribs adapted to coact with the peripheral grooves of units6b to prevent circumferated movement of the units in the chamber.

As in the other modifications described the positioned normal to theflow of gas. If desired units may be constructed in which a cat: alytictube is mounted concentrically within the casing. For example, catalyticmaterial may be packed in a tubular member made up of open mesh wire orperforated metal. This may be fitted within the chamber such that apredetermined space is established between the wall of the casing orchamber and the elongated perforated catalytic tube. By use of suitablebafiles the exhaust gas then passes from the exhaust pipe into the spacebetween casing and the catalytic tube and flows through the granularcatalytic material into the central open section of the perforatedcatalytic tube from which it is discharged to atmosphere. This type ofstructure thus serves effectively in the dual capacity of a mufier andcatalyst chamber.

It is particularly to be observed that by invoking the concept ofutilizing the catalyst packed unit tubes, spent catalyst units mayreadily be removed and replaced. Also, if desired the tube units may betreated so as to revivify the catalyst. By current replacement ofseveral old or spent catalyst units the emciency of the device maycontinuously be maintained.

It is to be understood that while a preferred embodiment of theinvention has been described this is given didactically to illustratethe underlying principles involved and not as limiting the invention tothe particular modification chosen for illustration.

I claim:

A device for association with the exhaust gas line of an internalcombustion motor which comprises an elongated tubular metallic casing, aspaced series of catalytic sections arranged lon gitudinally oi thecasing and defining expansion chambers therebetween, each sectioncomprising a group of laterally abutting open mesh tubular metalliccontainers having catalytic material packed therein, the containers ofone section being circumferentially displaced relatively to thecorresponding containers of an adjacent section.

. DON L. EASTMAN.

